The primary aim is to test the feasibility of accruing and retaining women in a clinical trial which requires the collection of biological samples and the assessment of intermediate markers of estradiol metabolites, cholesterol levels and its expoxides, 8-hydroxyguanine (8-OHdG), and mammographic density patterns. Also it will explore the feasibility of quantifying c-myc oncogene expression from breast cells obtained in nipple fluid.